This study used phylogenetic analyses of mitochondrial cytochrome b sequences to investigate genetic diversity within three broadly co-distributed freshwater fish genera (Galaxias, Pseudobarbus and Sandelia) to shed some light on the processes that promoted lineage diversification and shaped geographical distribution patterns. A total of 205 sequences of Galaxias, 177 sequences of Pseudobarbus and 98 sequences of Sandelia from 146 localities across nine river systems in the south-western Cape Floristic Region (South Africa) were used. The data were analysed using phylogenetic and haplotype network methods and divergence times for the clades retrieved were estimated using *BEAST. Nine extremely divergent (3.5–25.3%) lineages were found within Galaxias. Similarly, deep phylogeographic divergence was evident within Pseudobarbus, with four markedly distinct (3.8–10.0%) phylogroups identified. Sandelia had two deeply divergent (5.5–5.9%) lineages, but seven minor lineages with strong geographical congruence were also identified. The Miocene-Pliocene major sea-level transgression and the resultant isolation of populations in upland refugia appear to have driven widespread allopatric divergence within the three genera. Subsequent coalescence of rivers during the Pleistocene major sea-level regression as well as intermittent drainage connections during wet periods are proposed to have facilitated range expansion of lineages that currently occur across isolated river systems. The high degree of genetic differentiation recovered from the present and previous studies suggest that freshwater fish diversity within the south-western CFR may be vastly underestimated, and taxonomic revisions are required.

Aim The phylogeographic relationships among populations of the common Cape River crab, Potamonautes perlatus, are examined to investigate whether the contemporary population genetic structure is congruent with the hypothesized hydrographic evolution of drainage systems established during the Pliocene, or whether it reflects an older Miocene climatic amelioration.Location 139 samples of P. perlatus were collected from 31 populations distributed among the five major perennial drainage systems and a number of smaller catchments in the Western and Eastern Cape, South Africa.Methods Phylogeographic analysis using parsimony, maximum likelihood, minimum evolution and Bayesian inferences was employed for the 16S rRNA mtDNA gene region, while bootstrapping and posterior probabilities were used to assess the robustness of clades. In addition, nested clade analysis was performed in an attempt to disentangle the contemporary and historical factors that have sculpted genealogical relationships among conspecific populations of P. perlatus.Results Phylogenetic topologies were congruent irrespective of the evolutionary method employed. Two highly distinct reciprocally monophyletic clades characterized by marked levels of corrected sequence divergence were present, with no shared haplotypes between the two major phylogroups. Phylogroup one comprises the populations of the westward-flowing drainages (mainly the Berg and Olifants drainages), and phylogroup two comprises all of the southwardflowing drainages and can further be divided into two subclades -one containing the Breede River populations, and the other containing the Gamtoos and Gourits drainage systems. The nested clade analysis demonstrated restricted gene flow and long-distance dispersal for a number of higher clade levels. The higher-level groups and results for the total cladogram suggest either fragmentation or isolation by distance.Main conclusions Freshwater crabs are generally highly philopatric, and dispersal, although not common, has occurred historically. The westward-flowing drainages (Berg, Olifants, Eerste, Liesbeeck and Tokai) are isolated from the southward-flowing drainages by the Cape Fold Mountains, while the southwardflowing drainages have a number of tributaries that extend into the low-lying regions, allowing for gene flow between these three major drainages systems (Breede, Gamtoos and Gourits). Among the westward-flowing drainages, a more intensive sampling regime is required to understand evolutionary relationships. Our molecular results suggest that the observed patterns pre-date the formation of contemporary hydrographic patterns in the Cape. This suggests that an older Late Miocene event has severely impacted the contemporary population structure

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A new goatfish, Upeneus heemstra sp. nov. (Mullidae), from the Western Indian Ocean and SE India is described from initial DNA barcoding and quantitative morphological screening, followed by a taxonomic analysis featuring the comparison of 56 meristic, morphometric and colour characters compiled from 340 specimens of 10 phenotypically similar species. The new species differs clearly from U. oligospilus (Persian Gulf), U. tragula (Eastern Indian Ocean and West Pacific) and U. niebuhriresurrected here -from the Gulf of Suez (Red Sea) in the combination of the following characters: caudal peduncle, head, snout, postorbital, barbel and caudal-fin length, anal-fin and second dorsal-fin height, and the number of oblique bars on the caudal fin. These four species can be distinguished from the six other species of the so-called tragula group primarily by colour pattern and appear to represent a distinct 'dark-freckled' species complex. An updated identification key for the tragula species group is provided and remarks on size-related and population differences are made.